1. Field of the Invention
The present invention relates generally to collapsible or folding chairs. More particularly, the invention concerns a novel folding chair having a uniquely configured curved back support that provides superior back support for a person seated upon the chair.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Collapsible chairs are well known around the world as convenient options for seating at locations where seating is otherwise unavailable. They are easily stored, transported and set up for a variety of indoor and outdoor uses including camping, fishing, painting, sporting events, or concerts and parties. The time spent in these chairs is often over several hours. However, most of the collapsible chairs in use today do not have enough back support necessary for a healthy spine when used for sitting for these lengthy periods of time.
According to the American Chiropractic Association, one-half of all working Americans admit to having back pain symptoms each year and experts estimate that as many as 80% of the population will experience a back problem at some time in their lives. The importance of back-support in office chairs, where people sit for hours at a time, is well known to users and manufacturers. Entire fields of study within ergonomics and medicine have resulted from the magnitude of the need for proper posture when seated. However, a negligible amount of attention has been given to the importance of back support in folding chairs despite their widespread use.
A popular type of collapsible chair is the “sling” or “quad” chair where the chair membrane is supported at four points, two on the top of the chair back-rest and two on the end of the chair seat, creating a “sling” or hammock-like look and feel where the membrane sags in-between the four points of support. The problem with this configuration is there is no support for the back. And, unlike lying horizontally in a hammock, a seated person's back is closer to vertical which transfers their weight directly onto their spine. When seated in these types of chairs, a person's lower back bends to conform to the sagging curve of the membrane material, a direction that is the reverse of the natural curve of the lower back, thus placing tremendous stress on the intervertebral disks of the spine. This stress results in an often uncomfortable, sometimes painful, and always unhealthy, round curve of the lower back that can have long lasting effects on a person's quality of life.
Other collapsible chairs differ from the “sling” type chairs by having the chair membrane attached at more than four points. For example, some chairs have the membrane attached continuously along straight back support members. However, these chairs are only marginally better than the “sling” type configuration for back support. When a person sits in these chairs, their weight stretches the membrane, causing the same problem as found in the sling chairs; the lower back bends in the reverse direction from its natural curve to conform to the curve of the membrane material, thus placing unnatural stress on their spine. Even if the membrane could remain perfectly straight under a person's weight, these chairs would be inadequate because they would not match the natural curve of the human spine. That is, even straight chair-backs allow the spine to bend out of the natural, healthy, reverse-curved position.
Because people are different sizes and have different amounts of curve to their spine it stands to reason that any back support system needs to fit the needs of the individual. Some attempts have been made to make adjustable back support mechanisms in collapsible chairs, such as in U.S. Pat. No. 5,882,068 (E. R. Levine, 1999) but adjustable supports like these have disadvantages because they add manufacturing expenses, materials, weight, and tend to break more easily than chairs without moving parts. For chairs that are often used in harsh field conditions, these features are key considerations of distributors and buyers. Other collapsible chairs with adjustable back support, such as the Ergopod, have additional disadvantages in that they are visually unappealing due to strange “contraption-like” appearances.
It is therefore necessary to develop a collapsible chair that provides adequate back support that includes all of the advantages of existing collapsible chairs with no disadvantages due to the inclusion of a back support mechanism. As such, this chair should be easily set-up, collapsible, storable and transportable. It should also be visually appealing, durable, and fit the needs of a wide range of people.